Vickerson is now at a lean 285 pounds, down from his 321-pound playing weight last season. He shed the weight to better fit into coach John Fox's new 4-3 defense, where he will start at tackle. He played defensive end last season in a 3-4 scheme.

Vickerson -- who was signed during training camp after being cut by the Seattle Seahawks -- was a bright spot on a Broncos defense that finished dead last in football last season. The 28-year-old was rewarded for his production with a two-year, $4.75 million contract extension signed prior to the lockout in March. Because of the timing of the pact, he receives a $1 million bonus this summer regardless of labor strife.

"I'm happy with the deal, but I'm not satisfied," Vickerson said. "I still have to work. I still have to prove myself."

Fox retained defensive line coach Wayne Nunnely, a man Vickerson has formed a good relationship with. Fox has high hopes for Vickerson, who he sees as a player on the verge of taking his game to the next level.

"He's a young guy that has bounced around a little bit. I don't know if he's turned the corner, but he's definitely on the curve and a guy that we think can definitely help us," Fox said. "He's got a lot of the tools, physically, that we're looking for."

Vickerson was the only starting defensive lineman to attend the voluntary workouts organized by veteran safety Brian Dawkins. His attendance paired with his sleek new image are two signs the veteran is looking to entrench himself in Denver for the long haul.

"They expressed to me they want me to be the starter and be a vocal leader, so that's what I'm trying to do."